Mechanism for unloading compressors for starting.



.Ys. /1|K|v|/u\1. i MECHANISM fo uNLoAmNacoMPREssoRs ron summa.

APPLICATION mio Dc.a.19fa. g J; -5

' i Patented Ju11e26,` 1917."

` B.4 s..AY|KMAN.

MECIIMHSM FOR UNLOADING COMPRSSRS FOR STARTING.

` 4wl-'ucmon mm ums. ma.

1,230,834. Y vlamnmlJune26, 1917.

4 SHEiTS-SHEET 2.

` 'Inga of 5 /6 y '3. S. MKMAN. vMECHANISM FOR UNLOADING COMPRESSORS FO'? STARTING.

APPLICATION 'min ofc. s. 1913.

Patented June 2 6, 1917.

4 SHEETS-SHEET 3`.

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A if:

i ilUN;TEDsra'rns- PATENT BUn'roN' s." AI'KMAN, or MILWAUKEE, WISCONSIN, AssIGNon rro NATIONAL BRAKE a oFFoE.

COMPANY,- OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

MECHANISM FOR UNLOADING COMPRESSORS FOR, STARTING.

1 .esti334.v

lie it known that l.y l'inrros S. AIKMAN, i of the United States, residing at mo y during the starting of the motor so lha he motor may be brought. 'nearly or qui fullfspeed before the load of the coli ir is placed upon it. ln carrying v invention, lf make use of pneumatic hanisln by which the valves ,of I r are operated so as to prevent cmp] . the` t. le'ctivc `operation of' the compressor,

whichpneumatic'devices are under the conn trol;offvalve mechanism actuated automati- .L callyiby centrifuga] means operated. by the -motor. Thus. although the compressor 1s conn.

mechan coni'iected with the motor durting operation, it does not im.-

` anyt ing but`a frictional load upon the rduiiing the starting operation, as the "sion in `the compressor is relieved during the starting operation. y

My 'inventiciin isliarticularly applicable to electric motors (')tvtyliies having low starting "as for example, induction motors,

:in yconnection with this particular ystyle of motor.' y. l

By my invention I also control, by means of the pn'elrlmatic devices referred to. switchingfmechanlsm which will electrically control the circuitsof the motor so that suitable starting resistances may be employed for-Starting the motor, which are automatically cutout of circuit or short-circuited A when the motor has nearly or quite reached `full y s]`.)eed so to operate the pneumatic devices.

It will be understood that the centrifugal` mechanismand the devices actuated thereby, whetherpneumatic or rrechanical, for controlling the operation of the compressor, may be adjusted to operate when the vmotor has reached any desired speed,

Specification of Letters Patent.

Patented June 26, 1917.

Application filed December 6, 1913. Serial No. 804,959.

whethei this speed be full speed or not, and that 1n practice this speed will be taken of"4 a value corresponding to that at which theI motor has built up a sucient driving torque to carry the load of the c0mpressor.`

My invention consists broadly in means actuated by the centrifugal mechanism referred to by which the valves of-the compressor ,are controlled so as `to relieve or unstood than I do not lima myself to this ap'- y 'i plication as the controlling mechanism shownand described herein is applicable to con'ipressors generally,' regardless of the particular kind of fluid that they are intended to compress or pump.

The several drawings illustrating my invention are as follows: o

Figure l shows in sideelevation an electric motor, an air compressor driven therefrom, and my pneumatic controlling mechanism for unloading or relieving the compressor during the starting operation of the` motor.

Fig. Q is a `sectional view of the centrifu-I V gal meelninism'driven by the motor taken on a horizontal plane through the center o1 the motor shaft, taken along the line Q-2 of Fig. 3. i

Fig. 3 is a view of the parts shown in Fig.`

2 taken along the line 3-3.

`Fig. 4 is a sectional lview of theparts shown in Fig. 3 taken along the line i Fig. 5 shows in a view sin'lilar'to Fig. 4 the valve shown in .Ii`ig. 4 in itsalternate position. i

Fig.. is a detail view of in Figs. 4 and 5.

Fig. T is a view of the governing mechanism shown in Fig. 2 taken along thefline the valve shown Fig. 8 is a vertical sectional view taken through one of 'the suction valves of the compressor shown in Fig. 1. along a plane parallel with the motor shaft and shows the a couplin placing a 'load upon the compressor. y Flg. 9 shows 1n a vertical sectlonal view,

taken at right angles to the motor shaft a modified construction of centrifugal controlling means by which the compressor valves are controlled mechanically.

Fig. 10 is a verticalA sectional viewof the parts shown in Fig. 9, taken along the line 1O--1O.l

Fig. 11 is a View similar to Fig. 8, showing the application of the mechanical controlling means to the valves of the conipressor for relieving or unloading the same.

Fig. 12 is a cross sectional vlew of the loaded valve in the delivery main.

Similar numerals refer to similar parts throughout the several views.-

As shown in Fig. 1, the'motor 1, which is an electric induction motor, drives a shaft 2 which, b'y means of gearing contained in the housing 3, operates by means of a crank shaft and cranks the pistons in the comressor cylinders 4 and 5 in a manner wellnown in the art. The motor is indicated as connected with t-he shaft'2 by means of 6. Each of the cylinders 4 and 5 is provided with a reciprocating piston, as is usual in devices of this kind, andthe suction valves 7 and 8Y of the cylinders 4 and 5, respectively7 receive their air supply from a chamber 9 1n communication with the supply pipe 10. The air, after it is compressed 1n the cylinders 4 and 5, is'delivered to theV pipe 11 by which it is conducted throughthe check valve 12 to the storage tank 13.

`As indicated in Figs. 2 a'nd 3,the shaft -2 has rigidly secured to it a double bracket 14, to the opposite ends of which the centrifugal weights 15, indicated in Fig. 7, are

pivoted at 16 and 17.: These weights are provided with springs 18, holding them nor. mally toward the shaft'2 and determining the amount of their outward motion under the action of the centrifugal force due to the rotation aof the shaft 2. For convenience, two weights 15 are provided at each end of the bracket 14, one upon either side of said bracket, as this arrangement enables the mechanism to be contained in a smaller housing than would'otherwisebe the case.

T he two weights upon each end of the bracket 14 are connected together' inside of the bracket by a web 19 havlng an inwardly projecting rounded edge 'to engage the groove 20 formed in the. sliding collar 21 mounted upon theshaft 2. This sliding collar prevented from rotating upon the shaft 2 by means of a feather 22 upon which the'collar fits loosely so that motion of the collar longitudinally of the shaft is freely4 permitted. A second groove 23 formed in the collarA engages a pin 24 carried by the outer end of a short crank 25, which is se. cured to the inner end of the shaft 26 used to operate the valve for controlllng the pneumatic devices used to unload the com-V pressor. The end of the shaft 26 is flattened upon opposite sides to engage corresponding flats in the bore of the crank 25 so that the latter may be secured in proper angular position upon the shaft 26 without special adjustment and, fnrthermore,.it is immaterial in which of the two positions the crank 25 is placed upon theend of the shaft 26 as the two flats are parallel and of equal. extent. ThisI construction is used to facili-- tate the assembling of the apparatus.

The shaft 26 is supported in'a valve casing 27 having a tubular portion 28 tightly fitting into a corresponding opening in the sideof the casing inclosing the governor mechanism. The right-hand end of the shaft 26, as shown in Figs. 2 and 3, has a disk 30 formed on it resting against a flat face formed within the valve casing'27 and, by means of openings and ports in and through the disk 3() and in the casing-2T, the rotation of the disk 30 by means of the shaft 2 is madc to control the valve mechanism con.. nected with the suction valves of the compressor in a manner to be-described. It will be noted that the sleeve 2S extends through the casing 29 before the parting line of said casing,svo that the sleeve and parts carried thereby are not disturbed by the removal of the cap of the casing 29. to inspect the parts when desired. The shaft 26 has ex- -tending through it the bore 31 terminating contains a quantity of oil to be engaged bythe bracket 14 and the governor balls 15 as they rotate so that the parts contained withinthe casings 27 and 29 will be thoroughly lubricated at all times.

The valve casing 27 is provided with a 115 pipe connection 35 for supplying air under pressure to the valve and the ail-.thus supplied is communicated through a port 36 to the outer surface of the disk 30, thus serving in part to hold the disk against its seat. As shown in Figs. 4 and 5, the disk 3() has two diametrically opposite slots 37 formed through it and two diamctrically opposite orts 38 formed on its inner or va-lve sur a'ce midway between the slots 37. The valve casing 27.is provided with two outlet pipe connections 39 and 40 connecting, by ports 41 and 42 respectively. with circular openings 43 and 44, respectively,

in theface of the valve seat. The pipe'connection 39 is connected with the valve actuating cylinder 45 by meansvof a pipe 46, as shown in Fi 1, and the pipe connection 40 connecte with the switch actuating cylinder 47 by means of a pipe 48, shown :in the saine figure. The valve casing 27 has drilled through it and through the governor easing 29 into the interior thereof two exhaust holes49 and 50.

As a result of the construction described,

when the disk 30 is .in the position indicated in Fig. 4, Whichcorresponds to the position of the parts shown iii iFigs.' 2 and 3, the

; compressed air supplied to the valve casing 27 through the pipe connection 35 by means of the supply pipe 5l ,is ledthrough the port 4l and the pipe 46 to the valve controlling cylinder 45 and the switch controlling cylinder is eonnect'edthrough pipe 48 with the exhaust ,ort 49 by means of the left-hand one of t e 'recesses 38 formed in the valve face of the disk 30. When the shaft 2' is brought up to the desired speed for operating the switching mechanism and for throwing theconnjiressor into service, thc

i disk 30 is rotated by means of the governor mechanism described to th e posi tion in dicated a piston 52, the lower face of whichis subin Fig. 5, for ivliiclithe pipe 46 is connected with the exhaust port 50 by the right-hand one ofi the recesses `38 and the pipe 48 receives compressed air through the port 42 by means of which the switching mechanism is actuated. i i

The valve controlling cylinder 45 contains jected tok air pressure communicated by the 1Lii11 e46 to the port 53 leading through the cap 54` into the lower end of the cylinder 45. The `valve controlling cyliiider is pro- ,ivided with a lining `55; which may be `renewed ,when desired to make a proper fit with'the piston 52, and a piston ring 56 is employed in connection with the pistonl 52 for preventing leakage of the air around the piston during its operation, A disk 57 of suitable material, such as rubber or leather or composition of similar texture, is disposed in the upper end of the cylinder and held in place by a collar 58 to serve as a seat `for the upper end of the piston 52 when the latter is moved to its uppermost position so that the coperation of these parts serves to' counterbore. The tube 61 serres to retain ,inf place a spring 62 between the upper sur? face of the bottom of the piston 52 and a` shoulder formed a short distance above f the loiver end oi.' the plunger 64, which extends upwarcband loosely through the tube 6l to engage the P'ioiver end of the piston 65 of the suction valve 7 when the piston 52' isr i raised. The spring 59 serves to return the piston 52 to its lowerinost position when the air pressure in the cylinder 45 is released and the spring 62 serves as a cushion to permit the piston 52 to positively move the piston 65 up from its valve seat formed at its lower end, after which the spring 62 serves yto support the piston 65 with tbe'lower end of the plunger 64 clear from the `piston 52 so that the latter may be positively seateiil against the valve disk 57 without interference from thesuction valve piston 65, such as might occur if it were necessary teso' accurately proportion the parts that the piston 65 were required to be lifted clear of its scat and to its uppermost position hy means of a plunger rigidly in Contact or engagement with its operating piston. l

. As a result of the construction just described, it Will be apparent that when the piston 52 is raised by air pressure beneath it to lift the suction valve piston 65 to its uppermost position, the suction port 66 in communication with the chamber 9 and thus, through the pipe 16, with substan- V tially atmospheric pressure at all `times and,

as a result, the corresponding main piston' of thecompressor may move freely in either direction.

The operating mechanism or the suction valve 8 1s identical with that described fory the suction valve 7 and the only difference in the connections is that, for the suction valve 7 the port 67 extending horizontallyvv through the head 54 is connected at its lefthand end with the pipe 46 andv at its righthandend with the pipe 68, which latter communicates pressure to the valve cylinder for the suction valve 8, while the horirontalv port through the headf this valve cylinder is connected at/its left-hand end with the pipe 68 and is plugged in any suitable manner at its right-hand end.

The check valve 1,2 is preferably of theL spring-weighted piston type, the upper portion of its piston. being connected to the vatmosphere, the lower portion to compression pipe 1l, and when in its extreme lower position or non-pressure position,commimicaton liietween the pipe 1l and the reservoir 13 is disconnectml, so that for all pressures in the pipe 1l and tank 'L3 above a predetermined amount the valve will b'e raised from its seat and permit free communication of'air from the pipe ll to the tank 13. When', for any reason, the pressure in the pipe` 11. and tank ,are vformed as a continuation of the plull 13 drops below this ln'edeterlnincd amount the valve wlll close and prevent the flow ot air from the pipe 11 to the tank 13 until the of the piston 111. which is movable in thecylinder 112,.- The walls of the cylinder 112 which is screwed into the open top o the casing 109. A ground scat 114 co crates with the top of the piston 111 to orm a tight closure when the pressure in themain 11. becomes great enough to overcome the spring 115. It is to be noted that the top of the piston 111 is open to the 'atmosphere through the opening 116. This valve 12 is installed near the main reservoir so as to give ,the necessary pipe line volume between the compressor and this valve for operating the. valve relieving piston. The pipe 51 is preferably connected with the pipe 111 between the valve 12 and the compressor, as indicated, so that the requisite amount of pressure may be exerted upon the air supply to the centrifugal control valve immediatelyr after the motor has made a few rotations after having the compressor thrown into service by the valve control above described. When, for any reason, the motor 1 is stopped, the compressor is operatively disconnected froln theV motor, as above describcd and duringr the stopping operation when the motor has slowed down below its crit-ical speed for the governing mechanism, air is admitted under pressure from the pipe 51 to the cylinders 45, and the suction valves 7 and S are elevated from their seats to permit the motor-'to start freely' when it is next desired to start the same. t this time the pressure in the pipe 11 is maintained by the discharge valves of the compressor and if this pressure and the pressure in the tank 13 are above the pressure for which the valve 12 is set, the pipe 51 is in connection with the pressure in the tank 13, which air pressure is available when the motor is next started for controllingr the valve governing mechanism. lf, for any reason.v the air pressure in the tank 13 drops below the pressure `for which the valve 12 is set, the valve closes, trapping a certain alnount of air in the pipe 11 under the pressure for which the valve is set and this is available, for the opera-tion of the valve governing mechanism and. if it is not. the Iirst few strokes ofthe compressor will increase the pressure in pipe 11 to a s point sulicient to positively operate the devices controlled by the Agoverning mechanism. `When, by the subsequent operation of the compressor, the pressure in pipe 11 is increased above the value required to operate the valve 12, this valve is opened and the pressure in the tank 13 is built up until it is equal to the pressure in the pipe 11, at which time the valve 12 is fully moved to its open position, where it remains until the pressure to which it is'subjected drops below its operating value.

As a result of the construction and operation just described,-it will appear that when the tank 13 is of comparatively large capacity, as is many times the case, Vand when the operation begins with no air under pressure in the tank, the comparatively long-time interval which would otherwise occur before the pressure developed in the tank 13 reached the necessary value to operate the valve governing mechanism is avoided since it is only necessary to develop the necessary pressure in the pipe 11 as the valve governing mechanism is set to be actuated by a somewhat lower pressure than is required to operate the valve 12.

In connection with motors of larger sizes, it is desirable to employ resistanccs ($9. and 71 between the main line wires 72, 73 and 74 and the motor supply wires T5, 7G and 77, respectively, in order that the start.- ing current may not be abnormal. lVhen the motor has reached a certain speed. it is vdesirable to cut these resistances out of circuit for economical considerations and this is accomplished by providing` short circuiting contacts 78 for the resistance 69, shortcircuiting contacts 79 for the resistance 70, and short-circuiting contacts S0 for the re` sistance 71. Three contact strips 81, S2 and S3, supported by and insulated froml each otherby the bar 84 of insulating material,

are mounted upon the upper end ot' a plunger 85 connected at its lower end with a piston 86 contained in the cylinder 47, the dis` position of th' parts being such that when the piston 86 is moved upwardly` the contact strip S1 engages the contacts 7S, the contact strip/82 engages the contacts 79 and the contact strip 83 engages the contacts 80, thus short-circuiting these several contacts and, therefore. the resistances (S9. T0 and 71 without establishing connection in any way between the main line wires 72. 73 and 74 at the short-circuiting apparatus. A spring?,r S7 is disposed between the upper end of thc cylinder 4 7 and the upper surface ot thc piston 86 for the purpose of movingr the piston downward when the air pressure in the c vlinder 47 is relieved. From the description just given, it will appear that when the governing mechanism reaches its critical speed, the disk 30 by its rotation, not only relieves the pressure in the cylinders 45 but also communicates air under pressure through the pipe 48 to the cylinder 417, thus 40' '88 at 93 and 9,4, respectively.

placing the full-line potential upon themotor l. Similarly, when the motor is `stopped. for any reason and its speed drops 4"I Jelo'w the `critical speed for the governing meehanism,the rotationof the disk 30 relieves `the a'ir pressure in the pipe 48 and cylinder 47, thus permitting the contact strips 81, 82 and 83 to be moved downward, by the action of the spring 87, and out of engagementwith the corresponding shortcircuiting contacts at the same time that air pressure is placed upon the pistons in the cylinders 45 to relieve or unload the compressor cylinders.

As a result of theconstruction and operation4 of the valve 12 above described, `it will appear that the piston 8G is operated for the 20 first few operative strokes of the compressor,

even assuming that the tank 13 has practi cally lno air under pressure in it at .the time of starting the motor. This is a very desirable condition since Vfor large capacities of storage tanks a considerable time yinterval might elapsc before building up the pressure in the tanks to 'a suicient amount to operate the piston 86. In this way I provide for .eliminating the starting resistauccs before they have become unduly heated, Whether there is a supply under pressure at the time of starting the motor or not. l Y In the modified construction shown in Figs. 9, 10 and 11, the shaft 2 has rigidly securedkto it a cylindrical element 88 arrangedto rotate within the casing 8 9. The element `88 is provided with a counterbore 90 in which are mounted .two brake levers 91 and92, pivotally secured to the member Springs 95 and 96 arecontained in bores formed therefor'in the free ends of brake levers 91 and 92 and rest at their outer ends against suit- 'able seats formed therefor in .theinner surface .of thel counterbore formed in the element 88.- The brake levers illand 92 carry .,iibrake shoes 97 and 98, respectively, which rest upon the outer cylindrical surface of ai sleeve 9.9 .rotatably supported in 'alfixed l beai'ii'igllOO. The outer. end ofthe sleeve i99 has `drmed thereon Yor carried" thereby '.i'grooved pulley 101 for receiving a flexif f ble coirdor- 'wire 102 the end of whichv is sef. .cured to said pulley. The cord or wire 102 55,.isled thro'ugh thecasing 89, around a guide f roller.` 103, and by dther'similar guide rollf ,el S. -a's maybe necessary to reach the lower.

y end''tthe devices e riployed for controlling 1 lthejsuction valves r t; theE fcvornpressor as in- 6b dicated in Fig. 11. g llie i'necliaitism for conttrolling these valves` lrhay4 be identici l .with lat shown and Vdefzi'ibed abdivevvi h ithfe iT xtinon, instead. effi opelJ 'chanical means oonsistin rting inieii being lcompressed air, it is purely 'a me-l in'a cam 104 pivotally mounted at 105 1n the head 554 of the cylinder ela. The cam is provided with an operating lever 106, to the lowerr end of which theqcord or wire 102 is secured,` A second cord orrwire, yor, if preferred 'a rod 107' is employed to connect together the operating mechanisms .of the several cylinders 45 that may be used on a .compi-essor, depending upon the number of mainw'cylinders with which the com ressor i s provided. The parts contained wit in the counter-bore formed in the element 88 are] preferably inclosed by an annular plate ,i108`3scufredito the member 88 so as to'clear thefsleevf99.

As a result of the construction .just described, it will appear lthatvas the yshfalft 2 is rotated', the frictional engagement between the brake shoes 97 and 98, and the sleeve 99, due to the thrust in'wardlyfupon the brake levers 91 and 92, by thefsprings 95 and 96, will cause a rotary motion of said sleeve suiiiciently to move, the cordf'102nto the left, as shownl in Fig.L 11, for which condition the corresponding suctionivalve will be raised from its. sea'tvwiththe same effect as shown and described above for the construction indicated in Figs. l to' 8 Vin elusive. lVhen the speed of the shaftQ has increased to a critical value, for', which the weight `of the brake levers" 91"`and' 92 and the strengthA of the springs`95 and 96 are proportioned and adjusted, the centrif ugal torce. of the levers will release4 the sleeve 99, at which time the lsprigseiigag ing the pistons 52* willl force the pistons downward,` thus permitting thefsuction valves to return to their operating position. It will be apparenty that other mechanical devices muy be employed, if desired, for communicating motion ron the cain 104 to the plunger above it, the principal require ment being that motion of the 'camgshall move the plunger vertically a sufficient distance to hold the piston of the suction `valve from its seat until the cam moved 'to itsv releasing position, at whichitimetheplunger is released and the suctionlwilve is perl mitted to operate so listo throwthe loa-d. pon the corresponding compressor cylin er. i

In carrying out this construction, it, will be understood that the brakeshoes and 9 8 are preferably of material havinga coinparatively. high ,coeflici'ent of trictionri'vithout interfering with it having goodbearing surface, such, for example, as wood orlleather, and, if desired, the receptacle 4tained by said last valve for opeiiin While I have shown my invention in the embodiments herein described, it will be understood that I do not limit myself to these constructions as I may` employ many equivalents for carrying out m invention, as will at once appear to those s Killed in the art.

What I claim is:

1. In combination a compressor having avalve,said valve being adapted to be held open to relieve the compressor during start ing, a'delivery main, a tank, a loaded valv-e between said main and said tank for retaining a redeterniined pressure in said main upon initial loperation of said compressor, and means operated by the Huid pressure resaid til-st valve to relieve said compressor uring starting.

2. In combination a inotor,a compressor having a valve, said valve being adapted to be held open to relieve the compressor luring starting of the motor, a delivery main, a tank, a loaded valve between said niain and said tank for retaining a prtaleterinined pressure in said main upon initial operation of said compressor, means control ed by the pressure retained by said last named valve Ator hold-ing said first valve open,.and centrifugal means-for controlling said last means to restore said first valve to its seat.

3. In combination a fluid compressor, a suction valve for said compressor, a cylinder forliolding said valve vopen to relieve said compressor, a delivery main, a tank, a loaded valve between said main and. said tank for retaining a predetermined pressure in said main upon initial operation of said' compressor, and connecting means between said main and said cylinderv for disabling said suction valve by means of the pressure retained by said loaded valve.

4. Incombination a fluid compressor, an electric niotoi-.for driving said compressor,

a valley for said compressor, said valve being to be held open 4to relieve the coinpressor during starting of said motor, a tiuld pressure element tor'operatinv said valve to relieve the compressor, a delivery main, la

tank, a loaded valve between said main an'd said-tankior retaining in'said inain a predetermined, pressure upon initial operation of said compressor and a c oiinection between said pressure controlled clement and said main.

. In combination a. compressor, an inducltion motor for operatingr said compressor, a

suction valve for said conipressmga fluid Apressure element for holding` said suction valve open to relieve the com )ressoit dui-'ing starting of said motor,'a delivery main. a tank, a loaded valve between said niainand Said tank for retaining in saidl main pre determined pressure upon initial operation of said compressor, a connection between said main and 'said cylirider'andV a centrifu# gal-governor controlling said connection.

6. In combination, a fluid compressor, an induction motor for driving said compressor, a suction valve for said com ressor, a iston for holdin said valve off'o its' seat uring starting o said motor, a delivery main, a.-

tank, a loaded 'valve between said main and said tank, a connection between said piston and said main,. a valve in said connection, and a centrifugal governor connected to said motor,- said governor closing said valve-upon a predetermined speed of said motor.A

7. InA combination a compressor having a suction valve, a pistou and cylinder for disabling said suction valve, a delivery main, a

vporarily isabling [said suction valve, 'van electric motor, mechanisml foroperating the compressor from the motor, centrifugaldevices actuated vby t'h'e motor, v alve mechanism actuated by thev centrifugaldevices, compressed air `connections betvveen' the valvennechanism and tlieb valve controlling cylinders for operating the disabling connections when the speed of the motor is below a predetermined amount, a starting Y resistance in circnitwith. the motor, a sh0rtcircuiting switch, a plneuinatic cylinder for actuating said switc and a ipe connection from said pneumatic cylinder to the valve actuated by the centrifuga-l devices for short circuiting said resistance by means of said switchl when the speed of the motor reaches a predetermined value.

9. In combination; an 'electric motor, .a compressor, mecliai'iisin for driving the eoi n prcssor from the motor,s centrifugal governing mechanism actuated by; the motor, valve mechanism operated by the 'governing mechanism at n predetermined,speed of the' motor for unloading the compressor, a start# ing resistance in circuit with the motor, and' devices for short-circuitingsaidl starting re sistance by the operationv ofy the ,governing mechanism at a ypredeterniined speed' of the 10.y Tn combination, an electric motor, a compressor, :an -inwardly opening suction valve. for saidcompressor, mechanism be# tween the .motora and the coi-npressor 4for actuating the compressor, centrifugal governing mechanism` operated 'by the motor, devices actuated by the governing mechanism to hold the suctionrvalve away from its Seat until the motor rI .aches a. desired speed, a

asy

i erning mechai'iism motor.V y

starting resistance `in circuit with the motor,

and devices for short-circuiting said starting resistance by the operation of the gov- 11.]111combination," an electric motor, n

,'coiiipressoi, an inwardly opening suction valve for said compressor, mechanism be- 'tween the motor and the compressor for actuating the compressor, governing mechanism operated by the motor, devices actuated by the governing mechanism for pre- `ven`tiiigtlie closure of the suction valve until f the motor reaches a predetermined speed,

tor, and devices for sliortl'circuiting said starting resistance by the operation of the vgoverning mechanism at a predetermined speed of` the motor.

12. In combination, a motor, a compressor, mechanism for driving the compressor from the motor, a supply valve for the coinpressor, a delivery pipe for the compressor,

a receiving'tank connected with the delivery pipe, a pressure limiting valve in the delivery pipe, centrifugal governing mechanism operated by the motor, and devices controlled by the governing mechanism for disabling'said supply valve below a 'predetermined speed.

13. In con'ibination, an electric induction motor, a compressor, mechanism for-driving the compressor by the motor, speed controlled governing mechanismoperated by the motor for unloading the compressor during the starting of the motor, a starting resistanoe in the circuit of the motor, and switching mechanism operated by the governing mechanism for short-circuiting said `resistance when the motor reaches a prei determined speed.

14, In combination, an electric induction motor, a compressor, mecl'ianism between the motor and compressor for driving said compressor, speed controlled governing mechanism operated by the motor, a starting resistance in the motor circuit, and fluid aietuated switching mechanism controlled by `the governing mechanisml forgsliort-circuiting said resistance, said `governiiig mechaiiism includingr a valve for controllii'ig the operation of said switching n'iechanism at apredeterinined speed, said iiuid4 actuated switching niechauisi'n beingr supplied with Huid under pressure fron'iisaid compressor.

15. In combination, la motor, a compres-` sor, driving mechanism between the motor` "and compressor, a .suction valve, a plun- VIAand meclianisui fornirtiniting,said piston' "'65 ger for moving said valve away from its "at, a` piston" for ,operating said plunger,

during the starting; ot the motor and for reat `a desired speed of the leasing said piston and suction'lvalve when :the motor reaches a predetermined speed.

16. In an apparatus of tlie-classdescribed, the combination of a cylinder, a piston in saidcylinder, a sleeve Secured to `saidpis- 7 ton and forming a guide therefor-a spring `for returning said piston, said springsurroi'mding said sleeve, plunger in said `sleeve and a springbetween said plungerand said piston. u 7 17. In combination, a motor', al compressor, a suction valve for said' compressor, and' mechanism for rholding the suction valve from `its seat comprising a'cylinder,j. a

piston in the cylinder, a plunger between g@ the piston and the suction valve,'a seat for said piston limiting the movement thereof, a sleeveattached to said piston, :said sleeve surrounding said. plunger, a con'ipression ,spring in seid sleeve connecting the plung vger and the piston, and 'a for the piston.

18. In combination, a` motor,vafcoinpressor, a suction valve for said compressor, and mechanism for holding the suction valve from its" seat comprising e cylinder, aipiston in the cylinder, a. plunger between the piston and the suction valve, a. sleeve aty taclied to said piston, said sleeve `surrounding said plunger, a compression spring in 9 said sleeve between thel plungen and` the,

returning spring piston, a, returning'spring for the/piston,y

and a valve seat formed on the end .of the piston for holding the pressure in the cylinder when the piston is actuatedand for 1 limiting the movement of said piston.

y 19. In combination, a motor, a compressor, a suction valve for :saidl compressor, `mechanism for holding the suction valve from its seat con'iprising a cylinderg'ra piston in 1 the cylinder, a plunger between the piston and the -suction valve, a springgeonnection between the plunger and'tlic piston, and a returning spring for the piston, and valve mechanism operated by the motor` for sup- 1 plying compressed air to the cylindernduring the starting of the motor.

20. In combination, amotor, a compressor, a suction valve for said compressor, mech- :mism for holding the suction valve from itsv 1 seat comprising a cylinder, a piston in the cylinder, a plunger between: the pistoni and the suction valve, a spring connectionbetween the plunger and the piston, a returning spring for the piston, a valve seat formed the cylinder during the starting of the motor. l

ln combination a motor, a cou'ipressor, ai suction `valve for said comprl'ssor, mechanism for holding the suction,valvefroin itsseatf coinprisiiig acylinder, a piston 1n 13b between the plunger and the piston, and a .returningspril j; for the plston, governing the cylinder, a plunger between the piston and the suction valve, a spring connection mechanism actuated by the motor, valve mechanism actuated by the governing mechanism, and compressed air connections between the governing mechanism 'and' the cylinder for supplying compressed air to the cylinder during the starting of the motor.

In combination, a motor, a compressor,'

a suction valve for said compressor, mechanism for holding the suction valve from its seat comprising a: cylinder, a piston in the cylinder. a plunger between the piston and the suction valve, a spring connection between the plunger and the piston, a return- .ing spring for the piston, and a valve seat formed on the end of the piston for holding the pressure in the cylinder when the piston is actuated, governing mechanism actuated by the motor, valve mechanism actua-ted by the governing mechanism, and compressed air connections between the governing mechanism and the cylinder for supplying com-- pressed air to the cylinder during the startinder for supplying compressed air to thccylinder during the starting of the motor Q and for vreleasing ythe pressure in the cyl- Iluder when' the motor reaches a deslred speed.

. 1H. In combination,a motor, a compressor, a. suction valve for said compressor, mechanism t'or holding the suction valve from itsl seat comprising a cylinder, a. piston in the cylinder, a plunger between the piston and the suction. valve, a, spring connection between the plul'lger and the. piston, a returning spring for the piston, and a .valve 'seat formed on ythe end of the piston for holding the pressure in the cylinder when the piston is actuated, governing mech-v anism actuated by the motor, valve mechamsm actuated by the governing mechanism,

, and con'ipressed air connections between the governing mechanism and the cylinder for supplying. compressed an.' to the cylinder during the starting ot' the motor and Ifor releasing the pressure. in the cylinder wheny the motor reaches a desired speed.

In combmatlon, a motor, a compressor, a plurality of suction valves for saidanism and the cylinders for supplying compressed air to the ,cylinders durlng the starting of the motor.

26. In combination,l a motor, a compressor, a plurality of suction valves for said compressor, mechanism for holding each of the suction valves from its seat comprising a cylinder, a piston'in the cylinder, a plunger between the piston and said suction valve, a spring connection between the plunger and the piston, a returning spring for the piston, and a valve seat formed 011 the end of the piston for holding the pressure in the cylinder when the piston is actuated, governing mechanism actuated by the moto'r, valve mechanismactuated by the governing mechanism, and compressed air connections between thev governing mechanism and the cylinders for supplying compressed c air to the cylinders during the starting ot' the motor.

27. In combination, a motor, a compressor, a plurality of suction valves for said compressor, ,mechanism for holding each of the suction valves from its seat comprising a cylinder, a piston in the cylinder, a plunger between the piston and said suction valve, a spring connection between the plunger and the piston, and a returning spring for the pi ston, governing mechanism actuated by the motor, ,valve mechanism actuated by the governing mechanism, and compressed air connections between the governing mechanism and the cylinders for supplying compressed air to the cylinders during the starting of the motor and for ieleasing the pressure in the cylinders when the motor reaches a desired speed.

28. In combination, a motor, a compressor, a plurality of suction valves for said compressor, mechanism for holding each otsaid suction valves from its seat comprising a cylinder1 a piston in the cylinder, a. plunger between the piston and the' suction valve, a spring connection between the plunger and the piston, a returning spring for the piston, and a valve seat formed on the end of the piston for holding the pressure in the cylinder when the piston is actuated, governing mechanism actuated by the motor, valve mechanism actuated by the governing mechanism, and compressed air connections between the governing mechanism .and the cylinders for supplying compressed the cylinders during the starting of the motor `and for releasing the pressure in the,y cylinders When the motor reaches a desired s eed.

29. n combination',` a motor, a compressor ,having` an unloading valve, mechanism for driving the compressor from the motor, and `valvel mechanism for temporarily disabling the compressor by operating said unloading valve, a governor controlling said valve. mechanism, said valve mechanism comlprising a shaft, a disk on the end `of the sha having opposite slots formed ,therethrough and oppositel intermediate recesses formed in its valve face, and a casing forminga `valve seat for the `disk and having ports through it controlled hy said disk.

30. In combination, a motor,"a`con1pressor having an unloading valve, mechanism for driving the compressor from the motor, and valve mechanism for temporarily disabling the compressor by operating said unloading valve, a centrifugal governor operating at 'a predetermined speedgto, control said valve mechanism, said valve mechanism comprising a shaft, a disk on the end of the shaft having opposite slots formed therethrough and opposite intermediate recesses formed in its valve face, and a casing forming a valve seat for the disk and having port-s through itcontrolled bv said disk,

said shaft having a hole drilled through it for oiling the shaft and said disk.

3l. 1n combination, a motor, a compressor having anunloading valve, mechanism for driving the compressor from the motor, and valve mechanism for' temporarily disabling the compressor by operating said unloading valve, said mechanism comprising a shaft, a disk on the end of the shaft having opposite slots formed therethrough and opposite intermediate recesses formed in its valve face, a casing forming a valve 'seat'r `for lthe disk and having ports through it controlled by said disk, said shaft 'having at its operating end similar flattened sides, an operating crank disposed upon said operating end of the shaft in engagement with said flattened sides and a centrifugai governor for actuating said crank only upon the attainment of a predetermined speed of said motor.

32. As a means for actuating a valve, the combinationof a plunger for engaging the valve, a piston for operating the plunger, a cylinder containing the piston, and a spring connection between the piston and the plunger, the end of the piston 'forming a valve to maintain the pressure in the cylinder when :the piston is actuated.

33. As a means for actuating a valve, the combination of a plunger for engaging the valve, a piston for operating the plunger, a

cylinder containing the piston, a spring con- `nection between the piston the ger, the end of the piston forming a valve to maintain the pressure in the cylinder when the piston is actuated, and a valve disk in the end of the cylinder for engagement with the end of the pistonv en the latter is actuated.

3d. As a means for actuating a valve, the combination of a plunger for engaging the Avalve, piston for operating the plunger,

tuated, and a spring inffthe cylinder tend ing to return the piston to its releasing position. i

35. In combination,` an electric motor, a

compressor', mechanism between the motor and compressor for driving said compressor, a centrifugal governor operated by the motor, a starting resistance connected with the motor circuit, switching mechanism for eliminating the" resistance from the motor circuit when the compressor reaches a predetermined speed, a valve controlled by said governor and a'plunger controlled by said valve for operating said switchin meclnxnism, said plunger being supplie withiiuid under pressure from said conlpressor. 1

3G. In combination, an air compressor, a driving motor therefor, a starting resistance for the motor, a pressure-operated cylinder and associated 'mechanism for shortcir-cui ting said resistance, a delivery pipe for` ywith the element for disabling the suctionvalve, a centrifugal device for operating said valve to disconnect the `supply pipe from the suction-valve disabling-element -and to connect it to the pressure-operated cylinder' for short-circuiting the resistance.

37. In combination, a compressor comprising al suction valve, a motor for driving said compressor, an unloader arranged to temporarily retain said'suction valve in open position, and mechanism driven by the motor adapted to hold said unloaderin operative position when the motor is inert and during the time the same is being started.

In combination, a compressor comprising valves, a motor for driving said compressor, an unloader arranged to temporarily affect the compressor valves to render the compressor inoperative, and

mechanism driven by the motor adapted to hold said unloader in position to so ai'ect the valves when .the motor isl inert and during the time said motor is being started.

39. In combination, a compressor com-- tains a certain speed, `together with switching* mechanism arranged to eliminate the and mechanism resistance from the motor circuit'before the compressor is rendered operative.

41. In combination, a motor, a compressor driven-by the motor, a controlling device driven by the motor, a starting resistance in the motor circuit, devices normally rendering the compressor inoperative, said last-mentioned devices connected with the controlling device and adapted to render the compressor operative when the motor attains a certain speed, together with switching mechanism arranged to eliminate the resistance from the motor circuit before the compressor is rendered operative.

In witness whereof, I hereunto subscribe my name this 3rd day of December, A. D.

BURTON AIKMAN.l

Witnesses: y

THos. T. Bemis, R. H.' WEILAND. 

